A push by international groups has made shunning shark fin soup a popular environmental statement. But it remains a fixture in high-end dining establishments.

Reporting from Beijing — Tucked away on a glossy menu in the Herbal Cafe, a Beijing restaurant known for its herbal teas and low-fat Cantonese dishes, is a little nod to environmental advocacy. For about $2.50, customers can buy a bowl of imitation shark fin soup made of vegetable stock and potato noodles.

"If it was real, then you'd have to kill sharks," said Zhang Gui, the manager. "Sharks are very precious animals."

Demand for shark fin soup, once a dish for Ming Dynasty emperors, has skyrocketed in the last several decades as more people can afford to serve it at business banquets and wedding feasts, thanks to the growth of China's middle class.

But within the last few months, a strong push by international groups, with the help of a little star power, has made refusing to eat the dish a popular environmental statement akin to shunning furs or driving a Prius.

The San Francisco-based WildAid, which began campaigning against the shark fin trade in 2000, estimates that up to 79 million sharks are killed each year, many of them for their fins. This has led some shark populations to drop by as much as 90% within the last few decades, the group says, bringing some species to the brink of extinction and wreaking havoc on aquatic ecosystems.

China, Hong Kong and Taiwan consume 95% of the world's dried shark's fins, which are most commonly prepared as a gelatinous tangle in a chicken stock-based soup. Because fins are dried, skinned, bleached and treated with ammonia before they hit the market, it is nearly impossible to determine which fins come from which species.

The global campaign against shark fin soup has attracted some high-profile supporters. Celebrity chef Gordon Ramsay has pressured restaurants in London to stop serving the dish, and Richard Branson, chief executive of Virgin Air, has stopped his airline from transporting fins. WildAid's "celebrity ambassadors" include actors Harrison Ford, Kate Hudson and Ralph Fiennes.

A slew of Chinese celebrities, including actor Jackie Chan and former National Basketball Assn. star Yao Ming, began campaigning against the dish in 2006, with public service announcements produced jointly with WildAid spurring the fight at home.

In one 30-second spot that first aired on Chinese television in 2009, diners in an upscale restaurant are served bowls of shark fin soup while next to them a de-finned shark lies writhing in a tank. Yao, wearing a disapproving scowl, pushes his bowl away. "Remember: When the buying stops, the killing can too," he says.

The effort to ban shark fin is spreading. California has joined Oregon, Washington, Hawaii and Guam in banning the sale and possession of shark fin.

In March, Ding Liguo, a wealthy industrialist and deputy in the National People's Congress, proposed a ban to China's highest legislature, but the government has not yet taken steps toward implementation.

In November, the Peninsula Hotel Group, one of the most prestigious hotel chains in Asia, decided to stop serving shark fin, a move that took effect Jan. 1. In an emailed message, a hotel spokesman said that the ban had been met with understanding and praise in Hong Kong, Beijing and especially Shanghai, Yao's hometown.

However, shark fin remains a fixture in many high-end dining establishments throughout Beijing. At one plush-carpeted restaurant, A-Sen Abalone, diners can order a variety of innovative shark fin dishes, including stir-fried shark fin ($126) and shark fin served in a papaya.

When the environmental organization Green Beagle surveyed four- and five-star Beijing hotels in December, almost half of them said they had stopped serving shark fin, mainly for environmental reasons. But when the organization's representatives visited the hotels in the guise of customers, all but one establishment said shark fin was available.

Some shark fin connoisseurs are holding on to what they perceive as a bastion of traditional Chinese cooking and a boon to fisheries in poor coastal towns.

Li Dinggui, the general secretary of the Marine Products Assn. in Hong Kong, said the delicacy has been unfairly demonized. He argued that the oft-denounced practice of "finning," in which fishermen cut off the fin and roll the rest of the shark back into the water to die slowly, is not as common as environmentalists make it seem.

"To ban the shark fin, which is about 30% of the value of the shark, would be like banning fisheries in general," he said. "We should not ban what should not be banned."

Nevertheless, some restaurants in Beijing are beginning to notice the effects of the campaign. Zhu Yingxi, the manager of Jingde Xiaoguan, said the dish has not been selling well in recent months because of the economic slowdown as well as the pressure.

Zhu rejected the notion that shark fin soup is an important part of Chinese culture.

"It's a token of generosity in government and business," she said. "Culture is something that everybody has exposure to. Shark fin just isn't that type of thing."